Bad Acceleration!! Please help!!!!!

[electhrolite]

I have a 98 malibu 3.1 v6 about 116,700 miles, The problem is when I make a hard acceleration and the rpm increase rapidly, the car fails to continue accelerating just about 1 second and the resumes accelerating, but sometimes after a few seconds of the first failure it does it again. but as the car increase speed and the rpm start decreasing again the car resumes normal operation. It fails only when pressing the gas pedal aggresivily. Also the check engine light is on all the time, one time I took the car to garage to read the codes it they had 2 at that moment. It was random misfire and something about evap emissions faulty. I have used fuel injector, oil additivelike SLICK 50 , change fuel filter, air filter, spark plugs including the wiring. coolant flush, and still the problem. Have this happened to anyone? Do you fix? how? any suggestion? anything that could help will be very much appreciated. Thanks for the help in advance.

[HyperFox]

Have you changed the PCV valve? It would help if you had the exact codes. We could then chase this down...

[didi575]

I have a 2001 Chevy Malibu 3.1 V6 and two weeks ago I started having the same problem. I had the fuel filter changed and it didn't help and NOW I had the plugs and wires changed and my car runs hot, smells like something is burning and won't even go over 20 mph. If you have had this issue resolved can you please tell me what was wrong with you car. I REALLY NEED TO KNOW!!!

PS I had it hooked up to a scope and there are no codes reporting.

[HyperFox]

Ok.. Woah.. Slow down and breathe for a minute.. From what I can tell your car is overheating and has an issue or two..

Ok First things first.. Didi, you should post this in a seperate thread so you can get maximum exposure to your problem. This will help to pinpoint your issue that much more.

When the car wont go any further then 20mph how hard are you pressing on the gas? Is then engine screaming along ot does it seem stuck at a certain rpm? Is the car missing/knocking? Is your car modified, and how so? Is the PCV system working? Is your air filter clogged?

It kinda sounds like a fuel pressure regulator that is not working right.. Once the engine has cooled off, trace your fuel line to the fuel rail, unscrew the black cap on the line and underneath you will find a schrader valve (same thing as what you see inside of a valve stem of a tire) BE CERTAIN THIS IS A FUEL LINE. The a/c system will use a similar valves and it is under high pressure and will wreck your day if you drain it.

Turn the key to on and listen for the fuel pump to prime.. do this a couple of times. Press in on the scrader valve. FUEL WILL SPRAY OUT! (Id reccomend using eye and face protection at the least!)

If a trickle comes out. Id suspect a clogged line, faulty fuel pump, or regulator (assmuming the valve is after the regulator).

If the fuel sprays out like a fountain. Id suspect something else, such as clogged injectors, or any number of things.

Good luck

[didi575]

Ok I'm going to back a second....my b/f changed the wires and plugs and mixed up 1-3-5 and that's why it wasn't going over 20mph...now it's going over 20mph and is running better but it's not running normally to say. When it reaches about 15-18mph it decellerates and then you have have give a good excelleration to pick back up...better than before. However there is still a burning smell, kinda like rotten eggs. My b/f's thought is that it's the catalytic converter. What do you think?

[keepinit]

Bump....

My stepdaughter has a 05 Malibu with a similar issue. When attempting to accelerate, rpms go up but car won't go over 20mph. There is not a rough idle. Replaced MAF sensor at a friend's recommendation with no luck. Do I approach ignition? Fuel? Any help, even if a strategic plan of attack would help. Thanks.

[maxwedge]

4 year bump? In the future start a new thread, Anyway many things can cause this , low fuel pressure, blocked cat, bad misfire are the most common. If the rpms don't match the expected speed, is the trans shifting, is it slipping, only on site diagnosis can pin this down.